little puppy Posted July 8, 2019 Share Posted July 8, 2019 Patient- 2011 mack pinnacle mp8. My air compressor went out, when shop removed it the was a lot of tooth damage on the drive gear, mech. said he didn't see any other damage inside the block on any other gears. With a new compressor and gear they put it back together, i made it 250mls down the road, heard a noise it died immediately, after stopping looking it over, i tried to start it, it just spins freely, crank is turning real easy like it has no compression. Any ideas on what may or may not have happened? Thanks! Quote Link to comment https://www.bigmacktrucks.com/topic/58037-mp8-died-after-new-air-compressor-installed/ Share on other sites More sharing options...
1965 Posted July 8, 2019 Share Posted July 8, 2019 Yep; gear train blown up; probably idler gear bad; your mechanic made bad call! 1 Quote Link to comment https://www.bigmacktrucks.com/topic/58037-mp8-died-after-new-air-compressor-installed/#findComment-427294 Share on other sites More sharing options...
little puppy Posted July 8, 2019 Author Share Posted July 8, 2019 What's involved in fixing it? Quote Link to comment https://www.bigmacktrucks.com/topic/58037-mp8-died-after-new-air-compressor-installed/#findComment-427298 Share on other sites More sharing options...
1965 Posted July 8, 2019 Share Posted July 8, 2019 I myself haven’t did one; but have read on here that some have pulled engine & some did in truck. If it’s as bad as you say, it’s got metal all in engine. Its a bad situation! Quote Link to comment https://www.bigmacktrucks.com/topic/58037-mp8-died-after-new-air-compressor-installed/#findComment-427300 Share on other sites More sharing options...
little puppy Posted July 8, 2019 Author Share Posted July 8, 2019 I'm guessing the cam/ valve train is not turning, like i said when the engine spins its almost effortlessly like it has no compression at all. Quote Link to comment https://www.bigmacktrucks.com/topic/58037-mp8-died-after-new-air-compressor-installed/#findComment-427302 Share on other sites More sharing options...
fjh Posted July 8, 2019 Share Posted July 8, 2019 We just finished one in the shop roughly fifty hours into it tandem tandem mixer plus 10 grand in parts not a nice situation! 1 Quote Link to comment https://www.bigmacktrucks.com/topic/58037-mp8-died-after-new-air-compressor-installed/#findComment-427305 Share on other sites More sharing options...
little puppy Posted July 8, 2019 Author Share Posted July 8, 2019 Holy crap Quote Link to comment https://www.bigmacktrucks.com/topic/58037-mp8-died-after-new-air-compressor-installed/#findComment-427312 Share on other sites More sharing options...
fjh Posted July 8, 2019 Share Posted July 8, 2019 Yup and it was still running that’s the bad part for you yours is not 30 grand could go away in a hurry! Quote Link to comment https://www.bigmacktrucks.com/topic/58037-mp8-died-after-new-air-compressor-installed/#findComment-427319 Share on other sites More sharing options...
fjh Posted July 9, 2019 Share Posted July 9, 2019 1 minute ago, fjh said: Yup and it was still running that’s the bad part for you yours is not 30 grand could go away in a hurry! Unfortunately the dude who put the compressor on blew it big time when you got broken gears you need to go looking for why they broke! And these engines have a track record! Quote Link to comment https://www.bigmacktrucks.com/topic/58037-mp8-died-after-new-air-compressor-installed/#findComment-427321 Share on other sites More sharing options...
little puppy Posted July 9, 2019 Author Share Posted July 9, 2019 This really sucks Quote Link to comment https://www.bigmacktrucks.com/topic/58037-mp8-died-after-new-air-compressor-installed/#findComment-427334 Share on other sites More sharing options...
little puppy Posted July 9, 2019 Author Share Posted July 9, 2019 Any chance of valve to piston issues? Head damage? From when it let go? Quote Link to comment https://www.bigmacktrucks.com/topic/58037-mp8-died-after-new-air-compressor-installed/#findComment-427335 Share on other sites More sharing options...
41chevy Posted July 9, 2019 Share Posted July 9, 2019 (edited) At speed there's a good chance of valve damage minimum bent valves and possibly damaged pistuns Edited July 9, 2019 by 41chevy Quote "OPERTUNITY IS MISSED BY MOST PEOPLE BECAUSE IT IS DRESSED IN OVERALLS AND LOOKS LIKE WORK" Thomas Edison “Life’s journey is not to arrive at the grave safely, in a well preserved body, but rather to skid in sideways, totally worn out, shouting ‘Holy shit, what a ride!’” P.T.CHESHIRE Link to comment https://www.bigmacktrucks.com/topic/58037-mp8-died-after-new-air-compressor-installed/#findComment-427337 Share on other sites More sharing options...
little puppy Posted July 9, 2019 Author Share Posted July 9, 2019 I was running down the hwy, approx 1500 rpm when it happened.......so... Quote Link to comment https://www.bigmacktrucks.com/topic/58037-mp8-died-after-new-air-compressor-installed/#findComment-427338 Share on other sites More sharing options...
little puppy Posted July 9, 2019 Author Share Posted July 9, 2019 10 minutes ago, 41chevy said: At speed there's a good chance of valve damage minimum bent valves and possibly damaged pistuns That why i ask, because now it turns over like it has zero compression Quote Link to comment https://www.bigmacktrucks.com/topic/58037-mp8-died-after-new-air-compressor-installed/#findComment-427340 Share on other sites More sharing options...
fjh Posted July 9, 2019 Share Posted July 9, 2019 (edited) Sorry to say but in my mind right now you got mostly a big red boat anchor under your hood from what you have said! it may not be worth repairing this ! Due to the age of the unit! Edited July 9, 2019 by fjh Quote Link to comment https://www.bigmacktrucks.com/topic/58037-mp8-died-after-new-air-compressor-installed/#findComment-427359 Share on other sites More sharing options...
little puppy Posted July 9, 2019 Author Share Posted July 9, 2019 Pretty sad, truck only has 514k mls guess it is what it is. Quote Link to comment https://www.bigmacktrucks.com/topic/58037-mp8-died-after-new-air-compressor-installed/#findComment-427403 Share on other sites More sharing options...
1965 Posted July 9, 2019 Share Posted July 9, 2019 Very sad! Quote Link to comment https://www.bigmacktrucks.com/topic/58037-mp8-died-after-new-air-compressor-installed/#findComment-427404 Share on other sites More sharing options...
JoeH Posted July 9, 2019 Share Posted July 9, 2019 I haven't heard anything good about the MP series engines. I'm gonna stick to e7's for the next 20 or 30 years til they get their act together. Or I'll go Cummins. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/58037-mp8-died-after-new-air-compressor-installed/#findComment-427407 Share on other sites More sharing options...
Rob Posted July 9, 2019 Share Posted July 9, 2019 The Vee design two stroke Detroit Diesels ran rear mount geartrains for years and very trouble free. What is the difference with the MP8 geartrains from those? I've never seen an MP8 apart in person as far too new for me. 1 Quote Plodding along with no job nor practical application for my existence, but still trying to fix what's broke. Link to comment https://www.bigmacktrucks.com/topic/58037-mp8-died-after-new-air-compressor-installed/#findComment-427408 Share on other sites More sharing options...
1965 Posted July 10, 2019 Share Posted July 10, 2019 (edited) 41 minutes ago, Rob said: The Vee design two stroke Detroit Diesels ran rear mount geartrains for years and very trouble free. What is the difference with the MP8 geartrains from those? I've never seen an MP8 apart in person as far too new for me. It’s not because it’s at the rear; my understanding is that the idler gear has a nut that sets the tension & it’s threaded the way when it runs it backs off. (My understanding) why in the WORLD you would have it like that! I think now they use locktite. ???? Same as there cup & injector problems!! DD the flywheel housing held it. All the years I worked on DD never saw an idler bearing go down! Guess what I’m wanting to say is; them Volvo folks are stupid. Edited July 10, 2019 by 1965 1 Quote Link to comment https://www.bigmacktrucks.com/topic/58037-mp8-died-after-new-air-compressor-installed/#findComment-427411 Share on other sites More sharing options...
1965 Posted July 10, 2019 Share Posted July 10, 2019 They had a campaign, certain year models by vin. could get a pinning. They would drill a hole through bell housing into the locking nut to keep from backing off. Somewhere in there they knew which 1’s had locktite. Quote Link to comment https://www.bigmacktrucks.com/topic/58037-mp8-died-after-new-air-compressor-installed/#findComment-427413 Share on other sites More sharing options...
Rob Posted July 10, 2019 Share Posted July 10, 2019 I just pulled the #1 flywheel housing from a locked 8V-71 a week ago to scrap the engine. The idler gear will still roll on it's stub shaft and most likely pull right free. Doesn't make a lot of sense that another manufacturer would not follow that proven concept. 1 Quote Plodding along with no job nor practical application for my existence, but still trying to fix what's broke. Link to comment https://www.bigmacktrucks.com/topic/58037-mp8-died-after-new-air-compressor-installed/#findComment-427415 Share on other sites More sharing options...
little puppy Posted July 10, 2019 Author Share Posted July 10, 2019 Thanks for all the input guys! Quote Link to comment https://www.bigmacktrucks.com/topic/58037-mp8-died-after-new-air-compressor-installed/#findComment-427435 Share on other sites More sharing options...
fjh Posted July 10, 2019 Share Posted July 10, 2019 (edited) 3 hours ago, 1965 said: They had a campaign, certain year models by vin. could get a pinning. They would drill a hole through bell housing into the locking nut to keep from backing off. Somewhere in there they knew which 1’s had locktite. Another bandaid! They now lock tight and stake the nut horse is out of the barn though! Day late two dollars short! Edited July 10, 2019 by fjh 1 Quote Link to comment https://www.bigmacktrucks.com/topic/58037-mp8-died-after-new-air-compressor-installed/#findComment-427437 Share on other sites More sharing options...
Mack Technician Posted July 10, 2019 Share Posted July 10, 2019 12 hours ago, JoeH said: I haven't heard anything good about the MP series engines. I'm gonna stick to e7's for the next 20 or 30 years til they get their act together. Or I'll go Cummins. Stay gray(E7, E-Tech, ASET) till CNG or Battery gets here. Quote Link to comment https://www.bigmacktrucks.com/topic/58037-mp8-died-after-new-air-compressor-installed/#findComment-427447 Share on other sites More sharing options...
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